DIRECT 2.0 Space Exploration Architecture Performance Analysis Marshall Space Flight Center Analysis Performed: October 2007 May 2007 Introduction ♦ Compare and contrast system-level capabilities of the DIRECT architecture with the baseline Constellation Mission architecture • Use same tools, analysis processes, ground-rules and assumptions ♦ Assessment not meant to advocate one architecture or solution • Multiple launch vehicle and infrastructure solutions are suitable to carry out the Constellation Program Objectives • Reference NASA ESAS Report 2 Contents ♦ Background ♦ Analysis of DIRECT Architecture ♦ Comparison of DIRECT Architecture Performance with Constellation & Ares V Design Process / Groundrules and Assumptions ♦ Issues with DIRECT ♦ Appendix : OCT 2007 Analysis, MAY 2007 Analysis 3 DIRECT Background ♦ DIRECT is a proposed architectural alternative to Constellation, submitted to the AIAA by TeamVision Corporation ♦ DIRECT intends to cut costs by maximizing commonality with STS ♦ DIRECT’s alternative to the Ares V is the “Jupiter 232”, which is the focus of the analysis in this document ♦ Current (09/19/07) DIRECT Proposal is an update of the second revision (v2.0) of the DIRECT Architecture (Original released 10/25/06) 4 DIRECT Launch Architecture ♦ While DIRECT v2.0 emphasizes multiple possible lunar architectures, the document outlines a Contellation-comparable EOR-LOR mission using two launches of the Jupiter 232 ♦ The first launch is a fueled upper stage (EDS), while LSAM and CEV are launched together afterward ♦ LSAM and CEV dock with the EDS in LEO before TLI Jupiter 232 Configurations (Source: AIAA-2007-6231 fig. 96, pg. 79) 5 DIRECT Launch Architecture Jettisoned nosecone on ascent Partially Filled EDS Rear Rendz Claimed Mass: Adapter 98.3t Propellant EDS Nested LOX LSAM + CEV st Transfer Tank 1 Launch Claimed Mass: 71.8t Combined Vehicles +20.5t LOX Upper stage Structural expended shroud retained Total TLI Stack Delivery to LEO 2nd Launch Vehicles shown are notional, and do not indicate actual designs or relative sizes 6 Analysis of DIRECT Launch Architecture ♦ For assessing DIRECT claims, simulations are conducted first with DIRECT’s stated masses, then with masses calculated to fit the descriptions • 1st Step Used Direct masses and removed LOX transfer to get closer to Project Constellation mission guidelines ♦ Constellation IDAC-3 assumptions and ground rules are used in calculations and simulations (except where otherwise noted) • Sized vehicle with current ground rules and assumptions • 222km (120nmi) circular orbit at 28.5 degrees for LEO insertion orbit ♦ EOR-LOR TLI Stack is used as the comparison ‘common ground’ where the architectures are the most similar to the Constellation architecture 7 Summary Conclusions ♦ Analysis of the DIRECT architecture shows significant performance shortfall in assessed capability • The DIRECT architecture aggressively estimates its stage dry mass predictions, which results in optimistic in-space performance • Consequently, the Direct 2.0 would likely be a 3 Vehicle Launch Solution Mission to accomplish the Project Constellation Payload Requirements with NASA design margins, ground rules and assumptions ♦ Assessed performance has improved from May 2007 EOR-LOR but still fails to meet minimum requirements by at least 50% of needed Lander Payload. • (May 2007 Performance EOR-LOR was a ~13t to 15.5t Lander / Oct 2007 Lander ~21t vs 45t reqt) ♦ EOR-LOR introduces autonomous cryo-propellant transfer to achieve HLR mission. • Complex rendezvous prop transfer technology will require additional 1-2 flight tests to prove out. • Direct will lose ~25% (~12.5t to ~14t ) in assessed Lander by removing LOX Transfer technology • Would need to totally re-design an optimized Direct EDS for no LOX transfer to more accurately characterize this performance delta ♦ DIRECT currently unsuitable for its proposed goal of replacing the Ares I/V architecture to carry out the earth-to-TLI transportation functions for the Constellation Programs ♦ DIRECT Claims to be able to close the retirement gap from Shuttle to First Flight • Ares I from Start-up to PDR ~3 yrs (Summer 2005 to Summer 2008) • Assume 6 month program restart estimate (End of 2011 for PDR, Late 2013 CDR, 2015 test flight on Jupiter 120 ) • Estimate ~1 yr delay to Orion for Delta SRR and SDR may make Orion unavailable until at least 2016. ♦ DIRECT cost and safety claims lack supporting data and analysis ♦ Ares V has evolved to optimize both earth-to-orbit and orbit-to-TLI legs of lunar mission 8 • Results in significantly more lunar payload Comparison of DIRECT & Constellation Mission ~21t ~23.5t On-orbit stack mass at TLI initiation ~38.5t ~52t Assessed Performance Does not meet 45 t Lander Reqt Calculated LSAM mass based on available on-orbit EDS propellant, Vehicles shown are notional, and do not indicate actual designs or relative sizes EDS burnout mass, and fixed- mass CEV (45t Lander Reqt) 9 Observations of DIRECT Launch Architecture - Manufacturing & Cost - ♦ DIRECT uses ( 8 RSRB segment, and 2 RS68 for Crew Mission ) • Ares I : Uses 5 RSRB segments and 1 J2X Upperstage for Crew Mission • Per Mission costs for Ares I for Crew Missions are predicted to cost less than Jupiter 120 configuration. ♦ DIRECT assumes that all STS manufacturing infrastructure is still in place ♦ DIRECT claims only minor redesign of ET for 232 and 120 core stages • Assessment of design would lead to major redesign, development and qualification of Mod ET Core for 232 missions. • Predicted Touch labor of Ares 1 Upper Stage estimated to be significantly less than current ET touch labor. • Examined approaches like this in the past 20 years: − Concluded that this effort incurs significant expense and development with marginally applicable STS ET heritage: − the Jupiter common core requires a new : main propulsion system, thrust structure, avionics, forward LOX tank structure and a payload shroud, substantial intertank/LH2 modifications, and a stack integration effort. ♦ DIRECT EDS is a 2 J2XD system with different versions to accomplish the HLR Constellation goal. • Would require more on orbit loiter functionality and testing compared to Constellation Baseline • Cryo Prop transfer and rear rendezvous would incur significant technology development and flight testing 10 Observations of DIRECT Launch Architecture - Technology Development - ♦ DIRECT launch architecture proposes minimal early technology development effort for initial phase • Significant technology development initiated at lunar and Mars phases ♦ DIRECT launch architecture indicates minimal CFM technologies are needed even for 15 day loiter (maximum duration) of first of two Jupiter-232 launches (pre-position of mission propellant) • NASA Assessment of 15 day Loiter presents significant challenge to large partially filled Cryo-stage • On-orbit autonomous Cryo Prop transfer of (20.5t of LOX) requires significant enabling technology not in Constellation baseline ♦ DIRECT launch architecture does not identify minimum set of technologies and technology development plan for initial, lunar and Mars phases • No phasing plan of technologies throughout the entire program 11 Observations of DIRECT Launch Architecture - Test & Evaluation - ♦ DIRECT assumes minimal test requirements introduced by modifying Shuttle External Tank to Core Stage at its current size ♦ DIRECT does not provide a test strategy for any of the three identified launch architectures • No plans for propulsion, structural, IVGVT, aerodynamics, or SIL for major hardware elements and integrated vehicle for each vehicle configuration • No identification of test facilities required and corresponding facility modifications • No integration of Jupiter-232 test activities with Orion or Altair • No test schedule provided 12 Observations of DIRECT Launch Architecture - Operations - ♦ DIRECT launch architecture requires increased number of spacecraft separations and dockings for all phases, increasing risk • Separation, flip around and docking of Orion to Altair • Separation of new Orion-Altair stack from second EDS • Rendezvous and docking of Orion-Altair stack to first EDS pre-TLI burn • Separation of Orion-Altair stack from first EDS post-TLI burn ♦ DIRECT launch architecture alternative proposes reusable Altair located at Earth-Moon Lagrange point 1 (EML1) for lunar phase • Additional rendezvous and docking • Continuous real-time operations ground support for station keeping at EML1 ♦ DIRECT launch architecture alternative proposes propellant depot in LEO for Mars phase • Additional resupply and servicing missions needed to maintain depot • Continuous real-time operations ground support for station keeping 13 Observations of DIRECT Launch Architecture - Risk Mitigation - ♦ DIRECT launch architecture proposes carryover of much of the STS architecture to reduce mission and crew risk ♦ DIRECT shows a 1/1400 PLOC for Jupiter 232 Lunar / Mission • No substantiating analysis presented for Direct claim • Ares 1 : Current PDR Estimate is 1/2400 for contribution to PLOC (after 3 years of iterated analysis) ♦ DIRECT Claims significant reduction in PLOM compared to Ares V However: • LOX Transfer specific contribution not addressed and would be a significant contributor to PLOM • Appears no On-Orbit factors addressed (14 Day Loiter plus 4 day Loiter) ♦ DIRECT launch architecture does not identify key risks (performance, cost or schedule) or mitigation plans • No links to configuration/performance enhancements or technology enhancements 14 Observations